水下无人系统学报

Discussion about the Superdirective Beamforming Theory and Methods of Circular Acoustic Sensor Arrays

WANG Yong, YANG Yi-xin, MA Yuan-liang

2017, 25(新刊4): 297-309. doi: 10.11993/j.issn.2096-3920.2017.04.001

[Abstract](1558) [PDF 1316KB](1094)

Abstract:
To solve the contradiction between size and spatial directivity of sensor array due to space limitation of the carrier, such as unmanned undersea system, the supedirective beamforming methods were proposed to provide high directivity for a size-limited sensor array. This paper introduces the research background and history of superdirectivity, and presents the confronted problems and corresponding countermeasures. These superdirective beamforming methods can be classified into two main types, i.e., gain-maximation and beam pattern synthesis. Then, the common supedirective beamforming methods specially for circular acoustic sensor arrays are discussed in detail, and based on the above two main types, they are further categorized into the phase-mode method, the difference-based method, the eigen-beam decomposition and synthesis method, and the eigen-decomposition-based beam pattern synthesis method. The corresponding basic principles, merits and demerits, application ranges, relationship between each other and some related experimental results of these superdirective beamforming methods are analyzed to give a comprehensive presentation of the superdirective beamforming methods for circular acoustic sensor arrays, and to provide guidelines for related research and application.

A Brief Analysis of United States Unmanned Underwater Combat System

NIE Wei-dong, MA Ling, ZHANG Bo, ZHANG Long

2017, 25(新刊4): 310-318. doi: 10.11993/j.issn.2096-3920.2017.04.002

[Abstract](2288) [PDF 349KB](2679)

Abstract:
Unmanned undersea combat system(UUCS) is becoming the main force of undersea combat because of its low cost, high maneuverability and penetration, high safety and adaptability. According to the public reports and analysis, a working definition of UUCS is presented in this paper. Some U.S. UUCS projects are introduced, such as deployable autonomous distributed system(DADS), persistent littoral undersea surveillance network(PLUSNet), distributed agile submarine hunting(DASH), advanced underwater weapon system(AUWS), upward falling payloads(UFP) and Hydra. And the development status of several key technologies involved power technology, underwater sensor networks technology, communication technology, underwater integrated navigation technology and multisensor information fusion technology are an-alyzed. The development prospects of UUCS from technology and equipment are discussed. We hope that UUCS should be given adequate attention and be researched more widely and deeply.

UUV Navigation and Positioning Method Based on Model-Aided and Ocean Current Estimation

YAN Zhe-ping, SONG Jin-xue

2017, 25(新刊4): 319-325. doi: 10.11993/j.issn.2096-3920.2017.04.003

[Abstract](1208) [PDF 694KB](933)

Abstract:
For deep sea navigation, unmanned undersea vehicle(UUV) cannot track to the bottom because of the limitation of Doppler velocity log(DVL) measured distance. Therefore, a navigation and positioning method based on the UUV dynamic model is proposed in this paper. The estimation method of ocean current based on the extended Kalman filter is employed to calculate the ocean current information in UUV operating area, then the information is added into the UUV system model to compensate the errors induced by the model due to its unable perception of external environment, hence the accuracy of navigation and positioning is improved. Simulation proves the feasibility and effectiveness of the proposed method. This method is able to be applied to future UUV deep sea exploration.

Numerical Simulation for Ascending Trajectory of Submarine-Launched Carrier with Coupled Motion

LIANG Jing-qi, DANG Jian-jun, LUO Kai, HUANG Chuang, MO Hui-xia

2017, 25(新刊4): 326-331. doi: 10.11993/j.issn.2096-3920.2017.04.004

[Abstract](742) [PDF 902KB](403)

Abstract:
The unpowered ascending trajectory of a submarine-launched carrier presents large angle of attack and side-slip angle due to the effects of launching condition and ocean current, and then shows nonlinear characteristics. The conventional trajectory prediction method cannot meet the requirement of practical application. In this paper, a three-dimensional computational model with six degrees of freedom is established based on dynamic mesh and spatial kinetic equation of rigid body to achieve a two-way coupled simulation of the carrier and external flow field. The unpowered ascending trajectory of the submarine-launched carrier is simulated by changing the initial conditions, and the results are compared with that of the MK46 torpedo trajectory model. The comparison shows that: 1) the pitching angle gradually increases during the ascending process, while the angle of attack increases first and then decreases; 2) the ascent pitching angle and peak angle of attack decrease with the increasing launching speed; and 3) the duration of ascent and the pitching angle of breaking out of water increase with the increase in launching depth. This study may provide a reference for prediction of enhanced maneuvering trajectory of undersea vehicles.

Experimental Investigation on Characteristics of Vibration Excitation Sources for Undersea Vehicle Tail

DUAN Yong, GUO Jun, ZHOU Ling-bo

2017, 25(新刊4): 332-338. doi: 10.11993/j.issn.2096-3920.2017.04.005

[Abstract](1069) [PDF 1089KB](378)

Abstract:
To investigate vibration and noise of undersea vehicle tail, experiment was conducted in a large circulating water channel to understand the characteristics of vibration excitation source of the tail. The vibration response and radiated noise of the undersea vehicle tail shell were measured under the impacts of three main vibration excitation sources, i.e., the propulsion shafting, the hydraulic gear pump, and the propeller rotor. Then, the shell vibration response characteristics under the impact of each excitation source and the contribution of each excitation source to the vibration and radiated noise level were compared and analyzed. Results indicate that the hydraulic gear pump is the principal excitation source of the undersea vehicle tail, the propeller rotor is ranked second, and the propulsion shafting is ranked third. This study may provide a reference for research of vibration control technology of undersea vehicle tail.

Modeling Method of Torpedo Testability Based on Multi-Signal Model

ZHANG Zhao-xu, WANG Zhi-jie, LI Jian-chen, XU Jun, WANG Gui-qi, YANG Jin-hou

2017, 25(新刊4): 339-343. doi: 10.11993/j.issn.2096-3920.2017.04.006

[Abstract](725) [PDF 765KB](672)

Abstract:
Considering the characteristics of torpedo weapon system, a modeling method of torpedo testability based on multi-signal model is proposed. Then, a testability model at whole torpedo level is constructed by using the software TEAMS. Testability analysis, index prediction and design improvement are conducted to verify the feasibility of the proposed modeling method. This study may provide a feasible way to future design of torpedo testability.

Dynamic Modeling of Spiral Tube Evaporator Based on One-Dimensional Distributed Parameter Method

MIN Zhi-yong, DANG Jian-jun, SU Hao, ZHANG Jia-nan, LI Dai-jin

2017, 25(新刊4): 344-350. doi: 10.11993/j.issn.2096-3920.2017.04.007

[Abstract](590) [PDF 479KB](260)

Abstract:
The metal fuel with higher energy density has become an important role in development of underwater thermal power systems. In this paper, the one-dimensional distributed parameter method is employed to establish a dynamic model of the spiral tube evaporator in a Li/SF6 heat pipe reactor. Simulations are performed by changing different input parameters, and the results are compared with that of the moving boundary method. It is indicated that the one-dimen- sional distributed parameter model can better represent the real system, and is able to reflect the dynamic response of the system more accurately. The computational efficiency approaches that of the moving boundary model if suitable formula derivation and proper algorithm are adopted. This model is robust with respect to sudden change of the input load. This research may provide the basis for design, control and real-time simulation of underwater thermal power systems.

Simulation and Analysis on Radial Stiffness of Angular Contact Ball Bearing

LI Chuan-xi, DUAN Hao, WANG Yun

2017, 25(新刊4): 351-358. doi: 10.11993/j.issn.2096-3920.2017.04.008

[Abstract](715) [PDF 522KB](713)

Abstract:
Angular contact ball bearing is one of the key components in turbopump launch system, and its radial stiffness is vital for the performance of the turbopump launch system. To obtain reliable radial stiffness of the angular contact bearing, this paper derives a formulas for calculating the radial stiffness according to the Hertz contact theory and the geometrical relationship of the bearing. This formula considers the coupling of axial preload and radial load, the radial clearance, and the interference magnitude. Moreover, the nonlinear influences of different factors on the radial stiffness are analyzed. This study may provide a reference for integral analysis of rotating machine.

Influence of Sonar Detection on Detection Probability of Submarine Torpedo Weapon System

ZHANG Yong-feng, LI Zhi-wei

2017, 25(新刊4): 359-364. doi: 10.11993/j.issn.2096-3920.2017.04.009

[Abstract](998) [PDF 562KB](545)

Abstract:
When a submarine launches a wire guided torpedo in a hidden mode to attack a surface target, the front sonar detection ability of a weapon system significantly affect the detection probability and attack effect. This paper analyzes several sonar target detection factors influencing the detection probability, establishes a model by suing the present bearing guidance method and simulate the torpedo attack of the weapon system. Simulation reveals the change ruler of weapon system′s detection probability in the case of different torpedo initial attack distance and instable target tracking, and corresponding strategies and methods are given to provide a reference for torpedo attacking and engineering practice.

Wet Modal Analysis of Pressurized Structure in Launcher Simulation Experiment Based on Sound-Structure Coupling Algorithm

CHEN Wei-bin, DUAN Hao, WANG Yun

2017, 25(新刊4): 365-370. doi: 10.11993/j.issn.2096-3920.2017.04.010

[Abstract](1086) [PDF 680KB](641)

Abstract:
During launcher simulation experiment, the pressurized structure called false sea, is internally filled with water, the modal in this case is called wet modal. In this paper, the simulated and experimental results of a tube full of water are compared to prove the feasibility that the Workbench acoustic extension module can be used to carry out wet modal simulation based on the sound-structure coupling algorithm. Then, the method is employed to simulate the false sea′s wet modal. The simulation results of wet modal and dry modal are compared to obtain the influence of water on the natural vibration characteristic of false sea. This study may provide a reference for the research on wet modal of water-filled structures.

An Improved Design Method of Torpedo′s Wedge Ring Connection Structure for Enhancement of Supportability

CHEN Shao-qiang, WANG Hong-wei, LI Jian-chen, LIU Jin, ZHANG Jian-ting

2017, 25(新刊4): 371-376. doi: 10.11993/j.issn.2096-3920.2017.04.011

[Abstract](832) [PDF 805KB](572)

Abstract:
The existing researches on the wedge ring structures for connection of torpedo cabins do not consider assembly and disassembly in application, and pay insufficient attention to the supportability of the wedge ring structures. In this study, an improved design method of the wedge ring structure for connection of torpedo cabins was proposed according to the working principle of wedge ring. The new design takes convenient assembly and disassembly as well as enhancement of the supportability into account. Numerical simulation, assembly and disassembly test, and strength test were conducted to validate the improved design. Results show that the improved wedge ring structure meets the strength requirement of the cabin connection, and greatly improves the supportability of the wedge ring structure.

Design of Two Kinds of Multi-rosonant Broadband Longitudinal Vibration Transducer

HU Fu-ji, ZHANG Xi-shun, ZHANG Wen-bo, WANG Ming-zhou, GAN Hua-dong

2017, 25(新刊4): 377-380. doi: 10.11993/j.issn.2096-3920.2017.04.012

[Abstract](721) [PDF 828KB](302)

Abstract:
The longitudinal vibration transducer has been widely used in homing torpedo and undersea acoustic countermeasure because of its simplicity and stability. To reveal the performance of the multi-resonant broadband longitudinal vibration transducer, double- and triple-excitation broadband longitudinal vibration transducer are designed and fabricated. Both transducers are measured experimentally, and the results show that the measurement agrees well with simulation and compared with the double-excitation broadband longitudinal vibration transducer, the triple-excitation broadband longitudinal vibration transducer behaves in optimization and transmitting voltage response valley control. This study may provide a reference for the research of multi-resonant broadband longitudinal vibration transducers.

A Comprehensive Evaluation Method for Torpedo Loading Reliability Based on Multi-Source Test Information

XING Guo-qiang, SUN Chang-cun, LIANG Bin

2017, 25(新刊4): 381-384. doi: 10.11993/j.issn.2096-3920.2017.04.013

[Abstract](813) [PDF 339KB](263)

Abstract:
Loading reliability is one of the key performance indexes in torpedo operational application evaluation. However, the evaluation of loading reliability faces the problems of long test period, insufficient equipment platform, large sample size and high risk, which significantly influence equipping schedule of a torpedo. In this study, to evaluate this index scientifically and comprehensively, the comprehensive evaluation method of multi-source test information was adopted, and a comprehensive evaluation method of product reliability based on similar information was proposed with introduction of the environmental equivalent coefficient. In addition, finite time loading tests were carried out on an equipment platform and a no-equipment platform, and the results indicated that the proposed method could effectively solve the problems mentioned above, and could give more accurate evaluation of torpedo loading reliability.

2017 Vol. 25, No. 新刊4

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